Multi-stage differential amplifiers usually include separate stages each having a current source and load. Thus, duplicate circuit elements and excessive DC power loss due to current loads characterize these amplifiers.
Additionally, in microwave circuits a balun is required to couple a single-ended signal into balanced mixers or other elements that require a differential signal. However, baluns are difficult and expensive to integrate into Monolithic Microwave Integrated Circuits (MMICs) and baluns introduce loss which also increases the overall noise figure.